Transmitter



\ F. E. SUMMERS TRANSMITTER. APPLICATION FILED MAY12| 1919- 1,374,688.Pabenwd Apr. 12, 1921.

n is i r ST re s FRANK E. SUMMERS, or MEMPnIsMIssoURn TRANSMITTER.

T 0 all to 710m it may concern Be it known that FRAN E. SUMMERS, a'citizen of the United States of America, re-.

siding at Memphis, in the county of Scotland and State of Missouri, hasinvented new and useful Improvements in Transmitters', of which thefollowingtis a specification.

The purpose of the invention is to provide a new and novel form ofvariable contact for use in transmitters and similar apparatus, wherebymost effective variation of the resistance of the transmitter circuitmay be had. The improved variable contact element is adapted forconnection with other and similar elements, so that a battery of suchelements may be connected to and operated by a transmitter diaphragm.

The invention is illustrated and described in a specific embodiment, towhich, however, it is not to be restricted. The right is reserved tomake such changes or alterations i as the actual reduction to practicemay suggest, in so far as such changes or alterations are compatible inspirit with theanneXed claims. 7 Y 1 In the accompanying drawings:Figure 1 is a view in side elevation of the improved'variable contactmember showing the same attached to a transmitter diaphragm, a portiononly of which is shown.

Fig. 2 1s a section on the line 2 2 ofv Fig. 1.

Fig. 3 is a central verticalsectional view through the variable contactmember.

Fig. 4 is a section on the line 44 of Fi 1.

Fig. 5 is a side elevational view showing two variable contactmembersinterconnected with the foremost in connection with a diaphragm.

Fig. 6 is a detailed sectional view in which there is shown a modifiedform of electrode for the variable contact member.

Referring tothe drawings, the invention is shown as comprising aninflexible disk 1 made of insulating material, this disk abutting theside of a cap 2 formed with an external thread to receive the clampingring 8 which engages the outer periphery of the cap and holds the diskinto firm contact therewith. The interior space comprised by the cap andthe-disk 1 provides a chamber in which a variableresistance material 4may be carried. This variable resistance material is preferably carbongranules, but

Specification of Letters Patent. Patented Apr, 12, Application filed May12, 1919. Serial No. 296,530.

any other material'suitable to the purpose 8 may be employed. l The cap2 is made'preferably of metal; likewise is the clamping ring 3. Y 'Thedisk 1 is designed for attachment to a diaphragm such as that shown at 8in the drawings, and to this end carries a threaded stud 5'formed' withahead 6 lying against;

the inner face of the disk and carrying nut 7 bearing against the outerface of the latter. The stud is also secured to the diadisk, thussecuring the stud firmly to the phragm 8, being passed through thelatter bracket 14, this upright member 13 being secured to the cap'2 bymeans of a screw 15 whichfpasses through the upright an'd'engages in thethreaded hole 16 of a plate 17 the latter being attached to the cap2 by"suitable screws. I H

To oppose the pull of thevdiap'hragm 8, a

tension spring 18 is attachedone end to thescrew 15 and the other to ascrew 19, the latter being slidably mounted inthe upright leg of thesupport 14 and rendered adjustable by anut 20, the turning ofwhichobviously serves to regulate the tensionon the spring 18.

An upright 21 is mounted on the horizontal leg of the support 14 betweenthe upright member 13 and the diaphragm '8, and. this upright carries atits upper end an adjusting vscrew 22 and the vertical leg oi the bracket14 carries an adjusting screw 23 alined with the adjusting screw 22. 1Each of these screws has connected to it one end of a spring 24, theremaining ends of the ily respond to air vibration setup by the voice. vg In Fig.5 there are shown two of these variable resistance membersconnected in tandem, this manner of connection comprising the attachingof the stud 5 of one variable resistance member with the plate 16 of thenext.

In Fig. 6 there is shown a modified form of electrode. This electrode isformed with a shank portion 25 passing throughthe disk 1 for thereception of a nut 12, the shank carrying a conical head 26 lyingagainst the inner face of the disk-1 and having its conical surface incontact with the carbon granules 4:.

In the operation of the invention the vibration' of the diaphragm 8 as aresult of the sound waves set up by the voice causes the disk 1 and withit the cap 2 and the granules contained therein to vibrate, therebyvarying the intensity of contact between the granules and theelectrodes. This disturbance set up in the carbon granules effects avariation of resistance in the trans 1 in Fig. 5, it is to be noted thatthe grouping of the transmitter resistance structures in tandem, makesfor a more sensitive variation in the transmitter circuit, in that avariation is effected by each resistance element. Therefore the limitsbetween which the variations in resistance may take place is increased.

I The invention having been described, what is claimed as new and usefulis:

1. In a transmitter, the combination of a diaphragm, an insulating diskhaving connection with the diaphragm, a cap attached to the disk, avariable resistance substance carried within the cap, the cap havingmeans for attachment to a second disk, and electrodes carried by thesaid disk, whereby a plurality of caps and disks may be assembled intandem with the diaphragm.

2. In a transmitter, the combination with a diaphragm of an inflexibleinsulating disk,

a stud connecting the disk with the dia-.

phragm, a hollow cap against the open side of which the disk lies, aclamping ring threadingly engaging the cap and bearing against the disk,a granular conducting material carried in the cap between it and thedisk, electrodes mounted in the disk and in contact with the granularmaterial, and a resilient support for the cap for the'useful purposespecified.

3. In a transmitter, the combination with diaphragm of an inflexibleinsulating disk,

a stud connecting the disk with the diaphragm, a hollow cap against theopen side of which the disk lies, a clamping ring threadingly engagingthe cap and bearing against the disk, a granular conducting materialcarried in the cap between it and the disk, electrodes mounted in thedisk and in contact with the granular material, a resilient support forthe cap, and adjustablespring tensloning means for said support for theuseful purpose specified.

4. In a transmitter, the combination With a diaphragm, of an inflexibleinsulating disk, a rigidconnection between the disk and the diaphragm, ahollow cap against the open side of which the disk is disposed, meansdetachably securing the disk to thecap, a granular conducting materialcarried in the cap and contacting with the dislnelectrodcs mounted onthe disk and in contact with the granular material, and supporting meansfor the cap and the disk and permitting the same to vibrate bodily withthediaphragm to effect variations in contact between the granularmaterial. and the electrodes.

In testimony whereof he affixes his signature.

FRANK E. SUMMERS.

